Recent Advances of Carbon Dots with Afterglow Emission

Abstract

Carbon dots (CDs) have gradually become a new generation of nano‐luminescent materials, which have received extensive attention due to excellent optical properties, wide source of raw materials, low toxicity, and good biocompatibility. In recent years, there are many reports on the luminescent phenomenon of CDs, and great progress has been achieved. However,there are rarely systematic summaries on CDs with persistent luminescence. Here, a summary of the recent progress on persistent luminescent CDs, including luminous mechanism, synthetic strategies, property regulation, and potential applications, is given. First, a brief introduction is given to the development of CDs luminescent materials. Then, the luminous mechanism of afterglow CDs from room temperature phosphorescence (RTP), delayed fluorescence (DF), and long persistent luminescence (LPL) is discussed. Next, the constructed methods of luminescent CDs materials are summarized from two aspects, including matrix‐free self‐protected and matrix‐protected CDs. Moreover, the regulation of afterglow properties from color, lifetime, and efficiency is presented. Afterwards, the potential applications of CDs, such as anti‐counterfeiting, information encryption, sensing, bio‐imaging, multicolor display, LED devices, etc., are reviewed. Finally, an outlook on the development of CDs materials and applications is proposed.

Innovations in the Solid‐State Fluorescence of Carbon Dots: Strategies, Optical Manipulations, and Applications

“…Some CT states dissociate into CS states due to excimer complexes produced by photoexcitation, and the slow recombination of separated carriers leads to LPL (Figure 11b). [ 172 ]…”

“…Reproduced with permission. [ 172 ] Copyright 2023, Wiley‐VCH. c) CDs@Mn‐framework Composite design diagram.…”

“…The ideal band gap required for effective RISC to achieve TADF is less than 0.3 eV. [ 172 ] At present, CD‐based materials with TADF are constructed by dispersing the CDs into a substrate. A rigid substrate can form covalent or hydrogen bonds with the CDs, prevent oxygen quenching, protect and stabilize triplet excitons, and promote RISC.…”

Carbon Dot-Based Room-Temperature Phosphorescent Materials for Information Encryption

“…However, most CDs-based RTP materials only present phosphorescence in their dry state, which tends to quench in aqueous solution . This is not only due to the destroy of the hydrogen-bond skeleton by the water molecules but also the triplet state of the CDs is affected by the presence of dissolved oxygen in the aqueous solution, leading to the quench of the phosphorescence . Gao et al obtained M-CDs by reacting CDs with melamine, which exhibited phosphorescence in solution due to the construction of the hydrogen bonding network structure .…”

“…15 This is not only due to the destroy of the hydrogen-bond skeleton by the water molecules but also the triplet state of the CDs is affected by the presence of dissolved oxygen in the aqueous solution, leading to the quench of the phosphorescence. 16 Gao et al obtained M-CDs by reacting CDs with melamine, which exhibited phosphorescence in solution due to the construction of the hydrogen bonding network structure. 17 Song et al synthesized yellow RTP-CDs using a mixture of 1,2,4-triaminobenzene, magnesium salt, and phosphate.…”